https://gitlab.synchro.net/main/sbbs/-/commit/850de49a4c13adc69c000667  
  Modified Files:  
   .claude/skills/javascript/SKILL.md  
  Log Message:  
  javascript skill: a modified header must be read unexpanded  
    
  put_msg_header() refuses a header fetched with field expansion, and the  
  error it gives -- "Message header has 'expanded fields'" -- describes  
  the header rather than the call that produced it, so it reads as "this  
  message cannot be rewritten" instead of "your read was wrong". Since  
  expansion is the default, the obvious spelling of a read-modify-write  
  fails and the fix is not in the failing call.  
    
  Documents the expand argument on get_msg_header(), notes that the same  
  applies to headers taken from get_all_msg_headers(), and says to leave  
  expansion on for read-only callers -- it is what resolves the fields  
  they want. Also points at setting the field at save_msg() time, which  
  avoids the round trip where the original write is yours.  
    
  Sits with the sibling traps the section already carries: remove_msg()  
  silently returning false when handed a header object, and the lazy-field  
  gotcha. All three are calls that fail for a reason the symptom points  
  away from.  
    
  Co-Authored-By: Claude Opus 5 (1M context)   
  --- SBBSecho 3.37-Linux  
   * Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)